Load-sense circuits and valves are used more and more in hydraulic systems. Valves of this kind can be used in situations in which only one hydraulic pump provides the necessary flow and pressure to a hydraulic circuit having several actuators connected to it. With the load-sense valves, it is possible to control each of the actuators individually. The maximum pressure of the actuators can be controlled via pilot relief valves limiting the pressure of the load-sense lines.
In the case of two different actuators to be related by a pressure relation, a first actuator pressure can control a second actuator pressure in using a monitoring valve. The monitoring valve senses the pressure of first actuator and defines the load-sense pressure of the second actuator. Unfortunately, most monitoring valves induce unacceptable leaks from second circuit into the first circuit, and thus modify the first actuator's flow control. They also show high hysteresis, which is why their use in controlling pressures is difficult.